J. Phys. IV France
Volume 112, October 2003
Page(s) 1083 - 1086

J. Phys. IV France
112 (2003) 1083
DOI: 10.1051/jp4:20031070

Twin/domain pattern memory in aged Au-49.5Cd martensite

X. Ren1, 2, K. Otsuka3, A. Matsushita1 and M. Nakamura1

1  Materials Physics Group, National Institute for Materials Science, Tsukuba 305-0047, Japan
2  Japan Science and Technology Corporation (JST), Saitama, Japan
3  Nationallnstitute for Materials Science (NIMS), Advanced Materials Laboratory, 1-1 Namiki, Tsukuba 305-0044, Japan

We performed in-situ optical microscopy observations on a Au-49.5Cd single crystal during heatinglcooling and tensile loading/unloading runs. We found that for aged martensite domain pattern can be reproduced or memorized during heating/cooling or stress loading/unloading runs. This mesoscopic memory effect contradicts the basic notion of martensitic transformation that variants/domains are crystallographically and energetically equivalent. It points to the interaction of point defects with martensitic transformation. We show that the interesting mesoscopic memory effect can be fully explained by a general symmetry property of point defects, the symmetry-conforming short-range order property (Ren and Otsuka, Nature, 1997).

© EDP Sciences 2003